1. Field of the Invention:
The invention relates generally to electrical apparatus and more particularly to handle operating mechanisms for enclosed circuit interrupters.
2. Description of the Prior Art:
Circuit interrupters are widely used in industrial utilities and commercial applications to provide control of electrical circuits. Often these circuit interrupters must be located in environments where they are subjected to severe moisture or dust conditions or are even completely submerged. Thus it is required that they be mounted within sealed enclosures. These enclosures are often supplied with fittings to allow pressurization of the interior for leak testing and to prevent any possibility of water leakage into the enclosure.
It is extremely useful to be able to operate the circuit interrupter between its various operating positions without opening the enclosure, thereby eliminating the necessity for repressurization of the enclosure and preventing any possibility of operating personnel coming in contact with circuit interrupter components at high potential. Prior art operating mechanisms for enclosed switchgear were often located at the side of the enclosure, producing problems where installation space was limited. In addition, in order to obtain desired flexiblility it was necessary to provide for mounting of the mechanism on either side of the enclosure. This in turn necessitated an opening on either side of the enclosure, one of which was not used and had to be sealed. Alternatively, two styles of enclosures were required, one for left-hand mounting and one for right-hand mounting. Thus, it would be desirable to provide a control handle mechanism adapted for mounting upon the door of an enclosure. In addition it is desirable to provide a mechanism which will allow the door to be hinged from either side, and to provide for operation of the circuit interrupter despite minor misalignment of the door and enclosure.
In order to prevent unauthorized operation, it is desirable to provide capability to padlock the control handle in certain positions but to prevent the circuit interrupter from being locked into a closed position.
In many instances, enclosed circuit interrupters are installed in underground vaults and must be lowered into or raisee out of the vault by means of a crane or winch. Prior art control handle mechanisms were often susceptible to damage during the raising and lowering operation. Thus it is desirable to provide a handle which will minimize damage if struck when the enclosure is being installed or removed.
Often a circuit breaker must be operated from a remote location using a rope or lanyard. It is desirable to provide a handle which is adapted for such operation.
Safety considerations dictate that a circuit interrupter be opened mechanically as well as electrically. Thus it is desirable that a control handle mechanism provide for mechanical opening of the enclosed circuit interrupter.